This is a fly casting exercise for the Sexyloops Fly Casting Video Manual https://www.sexyloops.com/flycast/int...
It incorporates a number of elements, Mel Krieger's casting without a line, casting leader only, minimum power and so on. While it's good for beginners, it's been most useful for teaching fly anglers of 10-20 years fishing experience who have never ha a formal flycasting lesson.